Despite having taken vast historical liberties at times (Really? Four ME262's shot down in the air in the same dogfight? And weren't the Tuskegee Airmen known for flying P-51B's and C's -- not the D? But I guess "sex sells" applies to airplanes, too, and the D was the most disgustingly sexy plane of the war...), a rather predictable romance subplot (here's a clue--the guy who falls in love is the guy who dies in the last battle), some terribly wooden acting (especially the bomber crews, who sound like they're reading their lines off of a card), Red Tails contained quite a lot of very excellent airplane porn.
Make your own decisions on whether or not that matters to you--it's entertainment, not a documentary. And I should point out that it's probably going to be the last Lucasfilm movie I ever see, what with the way ol' George is looking down his nose at his fans.